The invention has particular application to use with receptacles containing blood which is to be processed. In a blood donation program, blood from each individual is received and stored in a separate storage bag for subsequent use and processing. It is important that blood which is so collected, remain separate from other donations and that the components which are extracted from the donated blood are also maintained separate to prevent contamination and to facilitate identification of the blood and its components with the donor. As a result it is usual that blood is collected in a flexible storage bag which may in many cases be associated with a number of interconnected bags. Subsequent to collection the initial storage bag which is substantially full at the completion of a donation can be subjected to centrifugation in order to provide two phases comprising one phase which is rich in red blood cells and a second phase which essentially comprises plasma which is rich in platelets. The plasma is then transferred from the first storage bag into an associated second storage bag. The two phases which have thus been separated may then be used or alternatively may be subjected to further centrifugation to facilitate further separation of additional components.
There is a difficulty however that is created in the further centrifugation of the two storage bags which is as a result of the circumstance that both of the storage bags are only partially filled. It has been found that when a partially filled storage bag is located in the bucket of a centrifuge, the gravitational forces which are induced by centrifugation, cause the bag to collapse into the bottom of the bucket and as a result of such collapse there is an inadequate separation of the phases of the blood products within the storage bag. This is because some of the contents of the storage bag are received in the folds and wrinkles which are induced in the bag as a result of its collapse into the bottom of the bucket of the centrifuge and the presence of the folds and wrinkles can inhibit the creation of a clear line of separation of the phases. Furthermore if a clear line of separation is created, it is difficult to maintain that line of separation on removal of the bag from the bucket.
In the past one method which has been proposed to overcome this difficulty has comprised inserting a partition into the centrifuge bucket which subdivides the space within the bucket into two or more zones and then inserting the partially filled storage bags into each of the zones whereby the partition and walls of the bucket tend to provide some support for the wall of the storage reservoir. It has been found however that as a result of the intense gravitational forces which result from centrifugation, the bags tend to migrate across the floor of the bucket and underneath the partition. This migration results in the creation of folds and wrinkles which inhibit the separation of the contents of the storage bag into its components as discussed above. In addition such migration can cause rupturing of the bags as a result of the partition being forced against a portion of the bag migrating underneath it.
Furthermore when it is necessary to centrifuge bottles or vials it has been found that the intense gravitational forces resulting from the centrifugation can cause the bottles or vials to burst. In addition if the bottles or vials are not snugly received in the bucket of the centrifuge as is the case with sample bottles or vials which are loosely received in the bucket the bottles or vials are more likely to suffer from deformation or breakage.